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Research background. Amaranth (Amaranthus hypochondriacus) flour produces films with excellent barrier properties against water vapor, allowing food preservation, but the mechanical properties are poor compared to synthetic films. One strategy to improve these properties is the incorporation of nanoparticles. The particles can also serve as a vehicle for the addition of antioxidant agents into the films. The objective of this work is to optimize the formulation for the preparation of amaranth flour films treated with antioxidant chia (Salvia hispanica L.) extract-loaded chitosan particles using response surface methodology (RSM). Experimental approach. Chitosan nanoparticles with the extract were synthesized by ionic gelation, and the films were made by the casting method. Three independent variables were assigned: amaranth flour (4-6%), glycerol (25-35%) and chitosan nanoparticles loaded with the chia extract (0-0.75%). We then evaluated the physical (thickness), mechanical (tensile strength, Young´s modulus and elongation), barrier (water vapor permeability, moisture and water solubility) and antioxidant properties of the films. The experimental results of the properties were analyzed using a Box-Behnken experimental design generating 15 runs with three replicates at the central point. Results and conclusions. Second and third order polynomial models were obtained from the ANOVA analysis of the evaluated responses, and high coefficients of determination were found (0.91–1.0). The water vapor permeability of the films was 0.82−2.39·10-7 (g·mm)/(Pa·s·m2), tensile strength was 0.33−1.63 MPa and antioxidant activity 2.24−5.65%. The variables had different effects on the films: glycerol negatively affected their properties, and the permeability values increased with increased amaranth flour content. The nanoparticles improved the mechanical, barrier and antioxidant properties of the films compared to the films without nanosystems. The optimal formulation was 4% amaranth flour, 25% glycerol and 0.36% chitosan nanoparticles. The optimized films had better mechanical (1.62 MPa) properties, a low water vapor permeability value (0.91·10-7 (g·mm)/(Pa·s·m2)) and moderate antioxidant activity (6.43%). Novelty and scientific contribution. The results show the effect of chitosan nanoparticles on the properties of amaranth flour films for the first time. The resulting equations are useful in the design of food packaging., Pozadina istraživanja. Brašno od amaranta odnosno šćira (Amaranthus hypochondriacus) može se upotrijebiti za izradu filmova s odličnim svojstvom propusnosti vodene pare, što omogućuje čuvanje hrane, no ti filmovi imaju lošija mehanička svojstva od sintetičkih filmova. Jedan od mogućih načina poboljšanja mehaničkih svojstava filmova je dodatak nanočestica, koje ujedno mogu poslužiti kao nosač antioksidansa. Svrha je ovoga rada bila metodom odzivnih površina optimirati pripremu filmova od šćirovog brašna dodatkom čestica kitozana koje sadržavaju antioksidanse iz ekstrakta chia (Salvia hispanica L.) sjemenki. Eksperimentalni pristup. Nanočestice kitozana s ekstraktom chia sjemenki dobivene su ionskim geliranjem, a filmovi su pripremljeni metodom izlijevanja. Određene su tri nezavisne varijable: šćirovo brašno (4-6 %), glicerol (25–35 %) i nanočestice kitozana s ekstraktom chia sjemenki (0–0,75 %). Zatim su procijenjena fizikalna (gustoća), mehanička (vlačna čvrstoća, Youngov modul elastičnosti i istezljivost), barijerna (propusnost vodene pare, vlaga i topljivost u vodi) i antioksidacijska svojstva filmova. Dobiveni su rezultati ispitani pomoću Box-Behnkenovog plana izvođenjem 15 eksperimenata s tri ponavljanja u centralnoj točki. Rezultati i zaključci. Analizom odziva pomoću ANOVA testa dobiveni su modeli oblika polinoma drugog i trećeg stupnja te visoki koeficijenti određivanja (0,91–1,0). Propusnost vodene pare bila je 0,82−2,39·10–7 (g·mm)/(Pa·s·m2), vlačna čvrstoća 0,33−1,63 MPa, a antioksidacijska aktivnost filmova 2,24−5,65 %. Svaka je varijabla imala drugačiji učinak: povećanje udjela glicerola negativno je utjecalo na svojstva flimova, a njihova propusnost se povećala s povećanjem udjela šćirovog brašna. Dodatkom nanočestica poboljšana su mehanička i antioksidacijska svojstva te propusnost filmova u usporedbi s filmovima koji nisu sadržavali nanočestice. Optimalni dodatak filmovima bio je 4 % šćirovog brašna, 25 % glicerola i 0,36 % nanočestica kitozana. Optimirani filmovi imali su bolja mehanička svojstva (1,62 MPa), malu propusnost vodene pare (0,91·10–7 (g·mm)/(Pa·s·m2)) i umjerenu antioksidacijsku aktivnost (6,43 %). Novina i znanstveni doprinos. Rezultati ispitivanja po prvi put prikazuju utjecaj nanočestica kitozana na svojstva filmova od šćirovog brašna. Dobivene jednadžbe mogu se korisno upotrijebiti u projektiranju jestive ambalaže.

The production of microbial biomass can be affected by the composition of the culture medium, including the content of salts and there is little information in terms of the NaCl concentration. Therefore, in this study, the effect of the addition of different NaCl concentrations (0.0, 2.0, 2.5, and 3.0 g L-1) in a Jourdan medium was evaluated on cell growth and physical and chemical properties of Arthrospira maxima cultivated in the region of Cordoba, Veracruz, Mexico. The experiment was established under a completely randomized design with a factorial arrangement (AxB). During the production stage, cell growth and morphology of filaments were evaluated, and after harvesting, the physical and chemical analysis (moisture, crude fiber, total protein and lipid content, mineral composition, photosynthetic compounds, antioxidant activity, and structural composition through FTIR-Spectroscopy analysis) of A. maxima was performed. Results obtained show that the addition of NaCl did not affect cell development, the morphology of the filaments, or the content of photosynthetic compounds. The maximum rate of biomass production in all treatments was at 6 d, without significant differences (p > 0.05) among treatments. In all treatments, A. maxima showed adequate concentrations of protein and minerals, as well as antioxidant activity. FTIR spectra showed absorption bands associated with proteins, carbohydrates, lipids, and nucleic acids. A decrease in the amide I and amide II bands of the proteins was observed with the addition of NaCl. A. maxima cultivated in these tropical climatic conditions had excellent properties to be used as a functional ingredient in the development of innovative and biotechnological food products for human consumption.

Green synthesis of gold nanoparticles using an aqueous coffee (Coffea arabica) pulp extract as a reducing agent was achieved and analyzed by response surface methodology, given the diverse applicability of these nanoparticles containing a wide range of phenolic compounds from the coffee pulp extract. Three factors (precursor concentration, reducing agent concentration, and reaction time) were considered and their combined effects on the maximum intensity (MA), particle size (d), and particle density (N) were analyzed. An opposing effect between the precursor and reducing agent was observed during synthesis because while the precursor increased d and diminished N, the reducing agent diminished d and increased N. These effects were observed simultaneously through the response surfaces of d and N. This methodology allowed the synthesis of nanoparticles with an average particle size between 5–22 nm and N around 2.9x1011−3.7x1013 (part/mL), depending on the response surface methodology, Box-Behnken design. The R2 value determined for all cases was 0.98 (MA), 0.99 (d), and 0.97 (N), clearly indicating that the model can be used to predict or design the response variables in the design space. Finally, Fourier transform infrared measurements showed that the organic compounds present in the aqueous coffee pulp extract were coating the surface of the gold nanoparticles. The proposed methodology could contribute to the design of new alternatives for the synthesis of specific nanostructures with potential applications in the therapeutic area.

Amaranth (Chitosan nanoparticles with the extract were synthesized by ionic gelation, and the films were made by the casting method. Three independent variables were assigned: amaranth flour (4-6%), glycerol (25-35%) and chitosan nanoparticles loaded with the chia extract (0-0.75%). We then evaluated the physical (thickness), mechanical (tensile strength, Young´s modulus and elongation), barrier (water vapor permeability, moisture and water solubility) and antioxidant properties of the films. The experimental results of the properties were analyzed using a Box-Behnken experimental design generating 15 runs with three replicates at the central point.Second and third order polynomial models were obtained from the ANOVA analysis of the evaluated responses, and high coefficients of determination were found (0.91-1.0). The water vapor permeability of the films was 0.82-2.39·10The results show the effect of chitosan nanoparticles on the properties of amaranth flour films for the first time. The resulting equations are useful in the design of food packaging.

Objetivo: Caracterizar el sistema de la oferta de Moringa oleifera Lam. en México. Diseño/metodología/aproximación: Recopilación y análisis de fuentes de información primarias, a través de entrevistas a productores e informantes clave que participan en el proceso de comercialización de los productos derivados de la moringa; en total fueron ocho empresas. Para recabar la información se utilizó la técnica de muestreo en cadena de bola de nieve. Resultados: El total de las empresas de producción de moringa iniciaron actividades hace menos de 10 años. Los dueños de las empresas son pequeños y medianos productores, con un promedio de 6.5 ha, caracterizados por un manejo orgánico y constante capacitación. Los principales productos ofertados en el mercado mexicano son: la hoja triturada, harina y cápsulas, cuyo principal mercado es el nacional. Por otro lado, se detectó que los productores en el mercado no interaccionan, lo cual genera asimetría de información. Sumado a ello se desconoce el inventario real del número total de productores y de empresas productoras de moringa en México, que limita la caracterización de la producción y de su beneficiado. Limitaciones/implicaciones: Los productores no son tan accesibles en cierta información, por ejemplo, la referente a los precios de venta de sus productos. Hallazgos/conclusiones: La moringa es un árbol multipropósitos con gran potencial, y no se cuenta con una base de datos de productores. Los productos ofertados son productos orgánicos y saludables. Sin embargo, faltan más investigaciones sobre la comercialización de moringa en México.

The aim of this study was to develop an edible alginate‐based film produced with turmeric (EFT), as an active compound, and evaluate its antioxidant capacity for application in fresh pork loin, beef loin, and chicken breast. The EFT was characterized by barrier parameters, color, and mechanical, structural, and antioxidant properties. Meat samples with and without EFT were stored at 4°C and analyzed at 2‐day intervals. The meat samples with EFT showed significant differences (p

The water vapor permeability (WVP) and hardness of biodegradable nanocomposite films based on glutelin from Jatropha curcas L. were determined and the results were analyzed by response surface meth...

A practical method to determine Staphylococcus aureus using bioconjugated gold nanoparticles is reported. The protocol uses gold nanoparticles stabilized by tetramethylrhodamine isothiocyanate labeled streptavidin followed by functionalization with biotinylated anti-staphylococcus aureus antibodies. The streptavidin stabilized gold nanoparticles were obtained by titration and analyzed by ultraviolet-visible spectroscopy and transmission electron microscopy. The obtained fluorescent bioconjugate selectively linked to the surface of S. aureus in samples contaminated with the microorganism, as demonstrated by confocal micrographs. The biorecognition process was performed by mixing the fluorescent bioconjugate with the sample. Bacterial dilutions from 1 × 108 to 1 × 102 cell/ml of S. aureus were determined, obtaining sensitivity values of 1 × 105 cell/ml by photoluminescence and 1 × 102 cell/ml by bioimpedance. This methodology represents a useful bioanalytical approach for the determination of Staphy...